Fluid electrode electric discharge device



jafil- 1932- R. RUDENBERG ET AL 1,839,502

FLUID ELECTRODE ELECTRIC DISCHARGE DEVICE Filed March 2, 1926 WITNESSES:INVENTOR w BY ,ATORE Patented Jan. 5, 1932 UNITED STATES PATENTQOFFICEREINHOLD RUDENBERG, OF IBERLIN-GBUNEWALD, AND RUDOLF G. BERTHOLD, OF

BERLIN-SIEMENSSTADT. AND KARL DONA'I' AND WERNER ESPE, OF BERLIN-CHARLOTTENBURG, GERMANY, ASSIGNORS TO WESTINGHOUSE ELECTRIC 8a MANU-FACTURING COMPANY, OF NEW YORK, N. Y.,-A CORPORATION FLUID ELECTRODEELECTRIC DISCHARGE DEVICE Application filed March 2, 1926, Serial No.91,755, and in Germany May 22 1925.

izes very quickly at the point where the arc touches the cathode, andreturns along the walls of the container in fluid form aftercondensation. It is known that such devices have a predetermined voltagedrop, depending upon the voltage drop in the fluid cathode,

or the cathode drop, a loss of voltage which varies with the distancebetween the anode and the cathode, and the anode drop. The voltage dropin the rectifier, however, means 29 a loss in the transformation oftheenergy in the device.

According to our invention, the loss of voltage in the container isreduced by adding metals or their compounds to the fluid cathode,whereby the electron emission of the cathode is increased. The increasein the electron emission is a consequence of the decreased loss ofvoltage, or the decreased work of emission, when the electrons leave the30 fluid electrode and enter the discharge chamher.

All of the metals of the first and second groups of the periodic system,that is, the alkali metals and the alkali earth metals, or theircompounds, have been found particularly adapted for this purpose. Suchmetals are, for example, barium, strontium, potassium, magnesium,caesium, and rubidium. Especially the last two metals, caesium andrubidium, are very well adapted for use as additions to a mercurycathode. The materials may be added'to the mercury in pure metallic formso that they will form an amalgam with the mercury.

It is also possible, however, to add compounds of these metals to thefluid cathode.

Obviously, the added materials may com-.

prise any desired number of different metals. The relative amount of theadded material is preferably so chosen that the emissivity of evenexceed the normal temperature in the condensing chamber. In order tomake complete condensation possible, in such a case, and to obtain agood return flow of the condensate into the cathode chamber, it has beenfound preferable to utilize special means for maintaining thetemperature of the condensation chamber and of the cathode higherthan-is the case in the usual uncooled discharge device. Special heatingmeans may be provided which will heat the condensation chamber and thecathode, and the discharge device may also be surrounded by aheatinsulating material which prevents a too rapid radiation of the heatproduced within the container.

Our invention consists in the details of construction and combinationshereinafter more particularly described and claimed and illustrated inthe accompanying drawing, the single figure of which is an elevationalview, partly in section, showing a preferred con- I structionillustrating the application of our invention to a rectifier.

In theiillustrated embodiment of our invention, a glass container 1 of amercuryvapor rectifier is of the usual shape, and is provided with anodearms 2, the mercury cathode 3 being amalgamated with one of theabove-mentioned metals of the first and second groups. In order to makepossible a certain condensation,-on the one hand, and a maintenance ofthe heated state of the metal compound, on the other hand, the glassvessel is surrounded by a heat-insulating cover member 4, and a heatingmeans, in the form of a spiral wire 5, is provided directly on thecontainer 1. Y

The admixture of metals of the first and second groups to the fluidcathode has also the advantage that the mixtures are resent in the metalvapor between the cat ode and anode. Consequently, the excitingpotential of this metal vapor is reduced, and thus the loss of'voltagein the rectifier is still further decreased. It is possible, therefore,in such devices, to make the distance between the cathode and the anodeslarger than ordinarily. This has the further advantage that the safetyagainst back fire is increased. For example, as shown in the drawing,the anode arms 2 can be made materially longer than usual. Consequently,the path for back fires is increased by double the amount by which theanode arms are lengthened.

Our new apparatus may also be utilized in discharge devices which haveno definite cathodes, as in devices serving for the passage ofalternating currents.

We claim as our invention:

In combination with a vapor electric device comprising an electrodecomposed of a liquid amalgam of mercury and material from the groupcomprising the first and second groups of the periodic table ofelements, two solid electrodes, and means adapted to reduce the rate ofheat outflow from said device, except in the vicinity of said solidelectrodes. 7

In testimony whereof we aifix our signatures.

REINHOLD RUDENBE'RG. RUDOLF G. BERTHOLD. KARL DONAT.

WERNER ESPE.

